In this project we seek to clarify and expand the nosology of the hereditary movement disorders, contribute to their understanding of their underlying biochemical basis, determine the most effective treatment for each, and suggest guidelines for counseling individuals at risk. General syndromes under study include the dystonias, tic disorders including Tourette syndrome, Huntington chorea and myoclonus. Approaches include standard epidemiologic and clinical genetic studies together with collaborative efforts in evaluating the role of neurotransmitters such as norepinephrine, dopamine, GABA, and related enzymes.